15 Mar
2017
15 Mar
'17
11:06 p.m.
On Wed, Mar 15, 2017 at 10:24 PM, degski via Boost
int x = 2 * 2;
is wrong in principle, correct would be:
int64_t x = 2 * 2;
This is what happens in the CPU.
Actually, no. Truncating multiplication is also quite common, and at least in case of x86 is faster than the widening. Some architectures (e.g. SPARC) don't even have a widening multiply instruction, so the operation would have to be emulated. Given that most of the time overflows are not a concern, I'd say truncating multiplication has the right to exist. Of course, the widening variant would also be a welcome option in the language, but hardly it should be the default.